The usual materials used for biomass briquetting are agricultural wastes. Examples of agricultural wastes include rice hull (shown on the left), corn husks, coconut shells, grass clippings, dried leaves, dried sticks and so on.
However, many non-traditional "wastes" have been incorporated into biomass briquette-making. Commercial wastes such as sawdust, paper and even charcoal powder have been used successfully in the production of biomass briquettes.
In the briquetting process that I've devised, I've had varying results in the use of some of the above mentioned biomass materials. Since the process involves compaction, the materials would behave differently when compacted.
Here are the various materials I've used:
- Paper - This is an excellent source. Offices would have tons of this waste readily available. This could come from old paper documents, manila folders, envelopes, stationery, carton boxes and so on. The nice thing about paper is that, properly shredded, it acts as binding material. But the fibers need to be exposed to create this effect. Tearing or shearing the paper achieves this rather than simply cutting it.
- Sawdust - This is an old standby and is easily available from sawmills, furniture and woodworking shops, and construction sites where woodwork is plenty. This is another excellent briquetting material.
- Dried leaves - This material is also readily available but needs to be very dry to completely break down manually into dried flakes. The main problem is consistency. Flakes vary in size, shape and thickness.
- Rice Hull or Husk - Although rice mills practically give this away in
sackfulls, I personally don't find it a good material in my briquetting process. The material is tough, springy and bristly to the touch. Finished briquettes may collapse easily if there's too much of this material.
- Charcoal Powder - Although touted for its good burning properties as a briquette fuel additive, I find it too messy to work with.
The next post in this series briefly discusses some of the briquette machines.